Pregnane derivatives and process



Patented F eb. 13, 195i Lewis Hastings Sarett, Princeton, N. J., o i'gnor" to Merck & Inc., Rahway, N. J., a corporation of New Jersey No Drawing. Application February 12, 1949, Serial-No. 76,205

This invention is concerned generally with steroid compounds and with processes for preparing'them. More particularly, it relates to an improved method for converting A --cyano pregnene compounds containing one or more nuclear hydroxy groupings to the corresponding keto-substituted 17(o)-hydroxy-2'5 keto-pregnanes.

This application is a oontinuation-ih-part of my'co-pending application Serial No. 778,465 filed October E, 19%? which, in turn, is a continuationin-part oi my co-pen'ding application Serial No. 773,525, filed September 11, 1947. I have disclosed in these parent applications that, when a A -20-cyano-pregnene compound is treated with osmium tetroxide and the intermediate osmate esterreacted with a hydrolyzing agent, there is obtained the corresponding 17(o) -hydroXy-20- keto pregnane compound. The 17 hydroxy group, introduced according to this novel method} isfobtained, surprisingly enough, in only one isomeric form, namely the a or natural configuration; i. e. the a hydroxy groupings in the compounds thus obtained have the same stereo chemical configuration as that present in many of the naturally-occurring adrenal hormones. This is of especial interestin' the preparation of pregneneA-diol 1'7 ((2) ,21-trione 3,11,20 (commonly known as Kendalls compound E) and its 21- acyl derivatives. These compounds are important as adrenal hormones or in therapy requiring adrenal hormone type compounds. They are furtherfluseful in the synthesis of similar hormones and compounds.

When a A -ZO cyano-pregnene compound contain'ing nuclear hydroxy substituents is treated with osmium tetroxide and the intermediate os'n'iate ester is reacted with a hydrolyzing agent,

the product obtained is the corresponding hydroXy-substituted 17 (o) -hydroxy-2O keto-pregnanei In the preparation of adrenal hormones,

such as compound E, it is ordinarily desired;

however, to prepare 17((1) -hydroxy-20-keto-pregnane compounds containing keto substituents attached'to the perhydrophenanthrene nucleus.- It was therefore an object of this invention to accomplish the conversion of A -20-cyano-pregnene compounds having one or more nuclear hydroxy substituents to the corresponding 17(a) -hydroxy- ZO-KetQ-pregnane compound wherein said nuclear hydroxy substituents have been oxidized to keto' radicals. A further object was to accomplish the oxidation of saidnuclear hydroxy radicals bya procedure which would not cause destructive, oxidationof other'portions'of the steroid molecule and which would" make possible the 22 Claims. (01. 260- 3914) convertedt'o ketoradicals'with I o-appreciable. loss in yield due todestructive'oxidation of the 17,20-

2 7 preparation of the, desired nuclear ketol-sulosti tuted 1701) hydroxy 20"- keto' pregnane compounds from the corresponding nuclear -hyndroi'ii.

ynteoA 20 oyano-prognene compoundsin good" yield and in a relatively'high state of purity. 4

I have found that this conversion can be' or:

complished by reacting osmium tetrokid'e with a A LZOwYanQ-pregnene compound which has at least one'nooloar yoroxy substituent (and which may have an ooyloxy substituen't attached t'o the" Carbon 'm) to forth the l'zzo-oomate';

ester ofthe correspondin nucIear hydroxylated,

17,20-dihydro5iy-20-cyetnh pregnane ooni-poun reacting this compound with an oxidizing age thereby oxidizing said oooleor' l'iydr'ony si1bstit'uout to a ket'o radical, and reacting the" resulting keto-substituted osmate ester with a agent. Moreover, the oxidation rea'c'tion utilized.

in this" conversion is accomplished with no oopro ciable destructive oxidation of other portions of.

the steroid. molecule; n A a It is indeed unexpected that this" oxidation or nuclear h'yor'oxy substituents in monomers esters of I'TBO-dih'ydrdxj} 20} cyano; preg'na rie compounds can be" carried out without affecting the oomato esterlinkaeessifice the l7,20 -oshiat group is ordinaril extremely seositivo to onidiiing agents, soon as ohrom o' acid. For oxomon, when the 1'7120-osmate ester of 3( ,1 '7',20ftrihy droxy-ll-keto-preehane is oxidizedwith acid u'nde'r conditions operative for the oxidation.

of the corresponding 20'-oyaoo-dorivouvo described in';this application, done of" theezipcted" l'7,20 -osmate of 3,11- d iketo 17,20-diliydro iypregnane is formed, I have discovered, however}- that wheiithej o-20 carbon atom' or the osmoro" ester isattac'hed to a cyano radical, the o'sm'ote ester is, surprisingly enough'very stable to oxidiocyano 17,20- dihydroxy preg'nane ompouodsi containingsecondary nucleanhy'dronyl groupings, can therefore heoxidi'ze'd to the corresponding drivative wherintlienucle'ar hydroziyl groupsare osmate grouping.

scribed in my co-pc'ndirig" application Serial No,"

77,268; filed r'lo'riiary isj 1949. sxamples r these starting materials" re? A -3 hydrOXy-ZU pregnene, A 3(a.) -hydroxy-20 cyano 21 acetoxy-pregnene, A -3,12-dihydroxy-20-cyano-2lacetoxy-pregnene, A -3 (a) -hydroxy-11-keto-20- cyano-2l-acetoxy-pregnene, and the like.

These A -20-cyano-pregnene compounds having at least one nuclear hydroxy substituent are treated with osmium tetroxide, preferably in the presence of an organic solvent such as pyridine,

thereby forming the 17,20-osmate ester of the corresponding nuclear hydroxylated 17,20-dihydroxy-20-cyano-pregnane compound, such as the 17,20-osmate ester of 3,17,20-trihydroxy-20-cyano-pregnane, the 17,20-osmate ester of 3(a),- 17,20-trihydroxy-l1-keto-20 cyano-pregnane, the 17,20-osmate ester of 3,12,17,20-tetrahydroxy-20- cyano-pregnane, the 17,20-osmate ester of 3(a) 17,20-trihydroxy-20-cyano-21-acetoxy-pregnane, the 17,20-osmate ester of 3,12,17,20-tetrahydroxy- 20-cyano-2l-acetoxy-pregnane, the 17,20-osmate ester of 3(a) ,17,20-trihydroxy-11-keto-20-cyano- 21-acetoxy-pregnane, and the like.

The oxidation of the nuclear hydroxy substituents in these 17,20-osmate esters of nuclear hydroxylated 17,20-dihydroxy-20-cyano pregnane compounds can be accomplished using strong oxidizing agents such as chromic acid, potassium permanganate, hypobromous acid, and the like. The oxidation is usually conducted employing chromic acid, preferably chromic acid in acetic acid solution. The reaction is conveniently carried out at room temperature, under which conditions, the reaction is substantially complete in about 30 minutes. The reaction mixture is diluted with a solvent such as methanolthen neutralized with a mildly alkaline substance such as aqueous potassium bicarbonate and the solvent and carbon dioxide evaporated from the neutralized solution in vacuo. The aqueous solution may be further evaporated to produce the 17,20- osmate ester of the corresponding 17,20-dihydroxy-20-cyano-pregnane compound wherein the nuclear hydroxy substituents hav been oxidized to keto radicals. Examples of these nuclear ketosubstituted 17,20-osmate esters of 17,20-dihydroxy-20-cyano-pregnane compounds obtained by, oxidation of the nuclear hydroxylated 17,20- osmate esters previously enumerated include: the 17,20-osmate ester of 3-keto-17,20-dihydroxy-20- cyano-pregnane, the 17,20-osmate ester of 3,11- diketo-17,20-dihydroxy-20-cyano pregnane, the 17,20-osmate ester of 3,12-diketo-17,20-dihydroxy-ZO-cyano-pregnane, the 17,20-osmate ester of 3-keto-l7,20-dihydroxy-20wyano-21-acetoxypregnane, the 17,20-osmate ester of 3,12-diketo- 17,20-dihydroxy-20-cyano'-2l-acetoxypregnane, the 17,20-osmate ester of 3,11-diketo-1'7,20-dihydroxy-20-cyano-2l-acetoxy pregnane, and. the like.

The 17,20-osmate ester of the nuclear keto-substituted 17,20-dihydroxy 20 cyano pregnane compound, thus prepared, is reacted with a hy-' drolyzing agent. Instead of isolating the osmate ester, however, the oxdation reaction solution may be used, after neutralization, in this hydrolysis operation. The preferred hydrolyzing agent comprises aqueous sodium sulfite and potassium bicarbonate and the hydrolysis reaction is conveniently carried out at room temperature. Under these preferred hydrolysis conditions the reaction is substantially complete in approximately 15 hours. The reaction mixture is filtered, evaporated to small volume and extracted with chloroform. The chloroform extract is then evaporated to dryness to produce the corresponding 17(a)- hydroxy-20-keto-pregnane compound having at least one nuclear keto substituent as, for example: 3,20-diketo 17 (a) hydroxy pregnane, 3,11,20-triketo-l7 (a) -hydroxy-pregnane, 3,12,20- triketo-17(a) hydroxy pregnane, 3,20 diketo- 17(a) ,21 dihydroxy pregnane. 3,12,20-triketo- 17(a.) ,21-dihydroxypregnane, 3,11,20 triketo 17(a) ,21-dihydroxy-pregnane, and the like.

When the 17 ,20-osmate ester of the nuclear keto-substituted 17,20-dihydroxy-20-cyano-pregnane compound contains a 21-acyloxy substituent, the hydrolysis operation described above can be carried out under mild conditions of hydrolysis thereby hydrolyzing the 17,20-osmate ester linkages without aifecting the acyloxy substituent attached to the 0-21 carbon atom thereby producing the corresponding 17(a) -hydroxy-20- keto-zl-acyloxy-pregnane having at least one nuclear keto substituent, such as .3,20-diketo- 17(a) hydroxy 21 acetoxy-pregnane, 3,12,20- triketo-17(a) -hydroxy 21 acetoxy pregnane, 3,11,20-triketo-17 (a) -hydroxy-21 acetoxy-pregnane, and the like.

Alternatively, a 17(a) -hydroxy-20-keto-21-hydroxy-pregnane having at least one nuclear keto substituent, prepared according to the first hydrolysis procedure described above, can be treated with an acylating agent, such as acetic anhydride and pyridine, to produce the corresponding nuclear' keto-substituted 17 (a) -hydroxy-20-keto- 21-acyloxy-pregnane.

The following examples illustrate methods of carrying out the present invention, but it is to be understood that these examples are given by way of illustration and not of limitation.

Example 1 429 mg. of A 3(a) -hydroxy-1l-keto-ZO-cyano- 21-acetoxy-pregnene (which can be prepared as described in my copending application Ser al No. 77,268, filed February 18, 1949) was dissolved in 4 cc. of benzene and 600 mg. of osmium tetroxide and 0.30 cc. of pyridine were added to this benzene solution. The resulting mixture was allowed to stand at room temperature for about 15 hours. The reaction solution was then evaporated to dryness in vacuo to produce the 17,20- osmate ester of 3(a) ,1701) ,20-trihydroxy-11-keto 20-cyano-21-acetoxy-pregnane, which was obtained as an amorphous residue.

The osmate ester, prepared as described above, was dissolved in 5 cc. of acetic acid and this solution was treated with coolin with 1.05 cc. of

acetic acid containing 3.52 mini-equivalents of sulfuric acid. A solution containing 250 mg. of

may be evaporated to produce crude 17,20-osmate ester of 3,11-diketo-l7(a),z0 dihydroxy-2fl-cyano-zl-acetoxy-pregnane.

The aqueous solution of the osmate ester Was treated with a solution containing 2.0 gms. of sodium sulfite and 2.0 gms. of potassium bicarbonate dissolved in 10 cc. of water, together with The resulting mixture was stirred for about 15 hours, filtered and evaporated,

10 cc. of benzene.

to one-half its volume'under reduced pressure,

extracted with chloroform and the organic layer evaporated to dryness. The crystalline product thus obtained consisted of 3,11-,20--trik'eto-1i7(e), ZI-dihydroXy pregnane; M. P. 233-235 C.

When the reaction described in the preceding paragraph was carried out employin 60 cc. of benzene instead of cc. and the mixture was stirred for eight hours instead of hours, the osmate ester grouping was hydrolyzed without affecting the acetoxy group in the 2l-position thereby producing as end product 3,11,20-triketo- 1'70) hydrox-y 21 acetoxy pregnane; M. P.- 223C.

The 3,11,20-triketo-l7 (a) ,ZL-dih-YGIOX-Y pregnane, obtained according to the first hydrolysis procedure described above, was dissolved in- 2 cc. of pyridine and 2 cc. of acetic anhydride was added to the resulting solution. The mixture was allowed to stand for 30 minutes and water was added to the reaction mixture thus formed thereby precipitating crystalline 3,11,20-triketolita) hydroxy 2L acetoxy pregnane; M. P. 223" C.

' Example 2 1 g. of A -3(a)-hydroxy-l1-keto-20 -cyanopregnene (which can be prepared as described in my co-pending application Serial No. 77,268, filed February 18, 1949) was dissolved. in 10 cc. of benacne and to this solution was added 1.0 gm. of osmium tetroxide and 0.6 cc. of pyridine. The resulting mixture was allowed to stand at room temperature for about 15 hours. The benzene was evaporated under reduced pressure from the reaction mixture thus obtained. The residual material was dissolved in 10.5 cc. of acetic acid and 2.21 cc. of acetic acid containin 3.52 milli equivalents of sulfuric acid per cc. was added to this solution. The resultin solution was cooled to 15 0., 9.2 cc. of 90% acetic acid containing. e mg. of chromic' acid wa added thereto and the resulting mixture was allowed to stand for 1 hour. About 4 cc. of methanol was added to the reaction mixture and the mixture was poured into a mixture of 40 cc. of water and 31.5 g; of potassium bicarbonate. The aqueous mixture was evaporated under reduced pressure ata temperature of 0., thereby removing the methanol and carbon dioxide. i I

An aqueous solution containing 4.0 gms, of potassium bicarbonate and 4.0 gms. of sodium sulfite was added together with 20 cc. of benzene to the foregoing solution. The resulting mixture was stirred for 5 hours, cc. of methanol and 20 cc. of benzene was added, and the resulting mixture was stirred for 15 hours. The resulting mixture was filtered, the filtrate was acidified to pH 6 and the methanol was evaporated therefrom unde reduced pressure. The resulting aqueous solution was extracted four times with chloroform and the chloroform extract was washed with water. The chloroform solution was evaporated under reduced pressure to produce 700 mg. of 3,11,20-tril:eto-l7(a)-hydroxy pregnane; M. P. 198-199 C.

Various changes may be made in carryin out the present invention without departin from the spirit and scope thereof. Insofar as these changes and modifications are within the purview of the annexed claims, they are to be considered as part of my invention.

I claim:

1. The process which comprises reacting osmium tetroxide with a n -pregnene compound having a cyano radical attached to the 0-20 carbon atom and havin at least one nuclear hyaqueous sodium sulfite.

6. droxy substituent, reacting the dsinate ester thus obtained with an oxidizing agent thereby oxdizing said nuclear hydroxy substituent to a keto radical, and reacting the resulting keto-substi-- tuted osmate ester with a hydrolyzing agent.

:0 (CN) CH3 attached to the 0-1? carbon atom, to form the. 17,20-osmate ester of the corresponding nuclearhydroxylated 17,20-dihydroxy-20-cyano pregnane compound, reacting this compound with an oxidizing agent thereby oxidizing said nuclear hydroxy substituent to a keto radical to produce the 17,20-osmate ester of the correspondin keto-- substituted 17,2O-dihydroxy-ZO-cyano-pregnane compound, and reacting this compound with a hydrolyzing agent.

4. The process which comprises reacting osmium tetroxide with a A -20-cyano-2Lacyloxypregnene compound having at least one nuclear hydroxy substituent, reacting the osmate ester thus obtained with an oxidizing agent thereby oxidizing said nuclear hydroxy substituent to a keto radical, and reacting the resulting keto-substituted osmate ester with a hydrolyzing agent.

5. The process which comprises reacting 0s mium tetroxide with a A -3-hydroxy-11-keto ZO-cyano-Zl-acyloxy-pregnene, reacting the" os mate ester thus produced with an oxidizing agent thereby oxidizing the 3-hydroxy substituent to a keto radical, and reacting the resulting ketosubstituted osmate ester with a hydrolyzing agent.

6. The process which comprises reacting osmihydroxy substituent to form the 17,20-osmate ester of the corresponding nuclear-hydroxylated 17,20-dihydroxy 20 cyano-pregnane compound;

reacting this compound with chromic acid there by oxidizing said nuclear hydroxy substituent to a keto radical to produce the 17,20-osmate ester of the corresponding keto substituted 17,20-dihydroxy-ZO-cyano pregnane compound, and reacting this compound with a hydrolyzing agent comprising aqueous sodium sulfite.

7. The process which comprises reacting osmium tetroxide with A -3(a) -hydroxy-keto-2 0-cy ano-pregnene to form the 17,20-osmate ester of 3(a),17,20-trihydroxy-11 keto 20 cyano-pregnane, reacting this osmate ester with chromic acid to produce the 17,20-osmate ester of 3,11- diketo-17,20 dihydroxy-20-cyano-pregnane, and reacting this compound with a hydrolyzing agent comprising aqueous sodium sulfite to produce 3,11,20-t1iket0:-17(a) -hydroxy-pregnane.

8. The process which comprises reacting osmium tetroxide with A -3-hydroxy-20-cyano-21- acetoxy-pregnene to form the 17,20-osmate ester of 3,17,20-trihydroxy-20-cyano-21-acetoxy-pregnane, reacting this osmate ester with chromic acid to produce the 17,20-osmate ester of S-keto- 17,20 dihydroxy-20-cyano-2l-acetoxy-pregnane, and reacting this compound with a hydrolyzing agent comprising aqueous sodium sulfite to produce 3,20-diketo-17 (a) ,ZI-dihydroxy-pregnane.

9. The process of preparing 3,11,20-triketo- 17(a), ZI-dihydrQXy-pregnane which comprises reacting osmium tetroxide with A -3(a)-hydroxy-11-keto-20-cyano-2l-acetoxy-pregnane to form the 17,20-osmate ester of -3(a)17,20-trihydroxy-ll-keto 20 oyano-Zl-acetoxy pregnane, reacting this compound with chromic acid to pro,- duce the 17,20-osmate ester of 3,ll-diketo-l 7,20- dihydroxy 20 cyano-2l-acetoxy-pregnane, and reacting this compound with an aqueous solution containing sodium sulfite and potassium bicarbonate for a period of time of at least about fiiteen hours.

' 10. The process of preparing 3,11,20-triketo 17(a) -hydroxy-2l-acetoxy-pregnane which comprises reacting osmium tetroxide with A -3(a)- hydroxy-l1-keto-20-cyano-2l-acetoxy pregnene to form the 17,20-osmate ester of 3(a) ,17,20-trihydroxy-ll-keto-ZO-cyano 21 acetoXy-pregnane, reacting this compound with chromic acid to produce the 17,20-osmate ester of 3,11-diketo- 17,20-dihydroxy-20-cyano-2l-acetoxy pregnane, and reacting this compound with an aqueous solution containing sodium sulfite and potassium bicarbonate under mild hydrolysis conditions.

11. The process which comprises reacting an' oxidizing agent with a 17,20-osmate ester of a l7,20-dihydroxy-pregnane compound having a cyano radical attached to the -20 carbon atom and having at least one nuclear hydroxy substit-V uent, thereby oxidizing said hydroxy substituent to a keto radical.

. 12. The process which comprises reacting chromio acid with a 17,20-osmate ester ofa 17,20- dihydroxy-pregnane compound having a cyano radical attached to the C20 carbon atom and having at least one nuclear hydroxy substituent thereby oxidizing said hydroxy substituent to a keto radical.

13. The process which comprises reacting an oxidizing agent with a 17,20-osmate ester of a 17,20-dihydroxy-20-cyano-2l-acyloxy pregnane compound having at least one nuclear hydroxy substituent thereby oxidizing said nuclear hydroxy substituent to a keto radical without affecting the esterified hydroxy groupings.

14. The process which comprises reacting an oxidizing agent with a 17,20-osmate ester of a 3,17,20-trihydroxy-11-keto-20-cyano-21- acyloXy- 'produce the 17,20-osmate ester of 3-keto-17,20-

dihydroxy-ZO-cyano-2l-acetoxy-pregnane.

18. The process which comprises reacting the 17,20-osmate ester of 3(a) ,17,20-trihydroXy-11- keto-20-cyano-21-acetoxy-pregnane with .chro-. mic acid to produce the 17,20-osmate ester of 3,11-diketo 17,20 dihydroxy-ZO-cyano-Zl-acetoxy-pregnane.

19. The process of preparing 3,11,20-triketo- 17(11) -hydroxy-pregnane which comprises reacting the 17,20-osmate ester of 3,11-diketo-1'7,20-

dihydroxy-20-cyano-pregnane with an aqueoussolution containing sodium sulfite and potassium bicarbonate.

20. The process of preparing 3,11,20-triketo- 17(a) -hydroxy-21-acetoxy-pregnane which comprises reacting the 17,20-osmate ester of 3,11-

diketo-17,20 dihydroxy- 20 'cyano-21-acetoxypregnane with an aqueous solution containing so-' dium sulfite and potassium bicarbonate under mild hydrolysis conditions.

21. The process of preparing 3,11,20-triketo- 17(a) -hydroxy-2l-acetoxy-pregnane which com-' prises reacting the 17,20-osmate ester of 3,11-

diketo-17,20 dihydroxy 20 cyano-21-acetoxypregnane with an aqueous solution containing sodium sulfite and potassium bicarbonate for a period of time of at least about fifteen hours thereby forming 3,11,20 triketo 1'7 (a) -hydroxy-21-hy-' droxy-pregnane, and reacting this compound with acetic anhydride to produce 3,11,20-triketo-17(a) hydroxy-2l-acetoxy-pregnane.

22. 3,11,20-triketo-17 (a) hydroxy-Zl-acetoxypregnane. LEWIS HASTINGS SARETT.

No references cited. 

1. THE PROCESS WHICH COMPRISES REACTING OSMIUM TETOXIDE WITH A $17-PREGNENE COMPOUND HAVING A CYANO RADICAL ATTACHED TO THE C-20 CARBON ATOM AND HAVING AT LEAST ONE NUCLEAR HYDROXY SUBSTITUENT, REACTING THE OSMATE ESTER THUS OBTAINED WITH AN OXIDIZING AGENT THEREBY OXIDIZING SAID NUCLEAR HYDROXY SUBSTITUENT TO A KETO RADICAL, AND REACTING THE RESULTING KETO-SUBSTITUTED OSMATE ESTER WITH A HYDROLYZING AGENT. 